This invention relates to fluid flow conversion and, more particularly, to processes and structures for converting the kinetic energy of fluid flow (e.g. the energy associated with wind, tidal and river flow) into mechanical, electrical and other power forms. For illustrative purposes, the invention is described in terms of its application to the conversion of wind power into electrical and other forms of power for the purposes of replacing or supplementing fossil fuel and other power sources.
The ever growing recognition that fossil fuel sources are exhaustible, environmentally polluting, and susceptible to powerful political exploitation, has led to a search for alternate power sources. Considerable attention in recent years has consequently been directed to the natural wind as a power source. See, e.g, the NSF/NASA workshop proceedings, Wind Energy Conversion Systems, NFS/RA/W-73-006, Dec. 1973.
Extracting power from the natural wind has a number of outstanding advantages. The supply is virtually inexhaustible and non-polluting. While the wind has been used from the beginning of recorded history to provide power for sailing vessels, for the milling of grain, and for the pumping of water -- and, more recently, for generating electricity -- its full potential has not been exploited because of the primary reliance on systems employing hydroelectric, fossil fuel, and atomic power sources. This is particularly so in the power utility field where these conventional sources have enjoyed substantial economic advantages.
Certain limitations have impeded wider use of wind power. Wind has a relatively low energy density and fluctuates in velocity and direction.